Pouring of floor 2's slabThe dead loads include the self-weight of the slab, floor finishes, walls, grills, etc. 2. If the weight of each steel beam is 62 lb/ft, determine the dead load in lb/ft supported by any interior beam. The height of the slab bolster is determined by the required concrete protective cover. Reduce evaporation over the slab by using a fog spray or slab cover. 2: Repeat and continue to draw complete (closed) shape. 8 of the Florida Building Code,. Figure B-10: Alternative Floor Slab Detail. Care should be taken to locate any reinforcement bars away from any anchor positions of the specific lift. For flat slabs like driveways and patios, spacing is roughly 18″ to 24″. get your rebar grid down, i would use 1/2" on 12" center. Common Rebar Sizes. 5" of XPS foam board underneath, 1150 square feet, 7 feet below ground. 1. 8. 2. For live loads of about 50 psf (2. Standard concrete floor slab thickness in residential construction is 4 inches, five to six inches is recommended if the concrete will receive occasional heavy loads, such as mortar homes or garbage trucks. 125mm. For columns and beams, the minimum spacing should be 6 inches. rebar strength is in tension, so by adding rebar to BOTTOM of foundation, it counter acts the load of compression. Construction joints also have this spacing for strip placement of the concrete. Before placing the re-bar, correct spacing given in the detailing drawing were marked by using piece of choke on the slab formwork. Minimum thickness of concrete structural elements based on ACI 318-14, IRC 2009, IS 456 2000, and UBC. The fibers must be high quality and tested to verify consistent strength. Detail A: “Snap Tie” (diagram upper left) is the simplest and is usually used for rebar in a flat horizontal position. 96-8. Section 13. In the case of the RCC slab, the maximum spacing between two secondary parallel wires should be 5D or 450 mm or whatever. 9836 – 18. For example, at Column I-4 between the basement and first floor, building plans required four pieces of horizontal rebar through the column in both directions to connect it to the slab. A concrete slab costs between $4. of the most advantageous location for a floor opening depends on the type of two-way slab you’re designing or evaluating. 53 Compute moments At support: ( - ) M1 = 3. Ilang Araw Ang Pagbuhos Ng Simento? In this video, I'm sharing you the process of concrete pouring and sizes/spacing of rebars for the beams and slab concrete for the. Rebar spacing calculator is perfect to indicate how much Rebar is needed. 8 mm) when subjected to 50 pounds (23 kg) applied over 1 inch square (645 mm) of material and are greater than 1 / 8 inch (3. 5 inches up to 12 inches. 1 can be used for these purposes. 20mm clear cover is sufficient for intermediate floor slabs, and 30mm clear cover should be provided for roof slab exposed to rain (c). then use 1/2 PEX tubing and create about 5 floor heating circuits, bring all of them to a convenient access point in the shop. 1 the spacing of links along the FULL HEIGHT shall not exceed 6 times diameter of smallest longitudinal bar or 150mm. -l. What size rebar do I need for a 6 inch slab? The size of rebar needed for a 6 inch slab would depend on the specific application and requirements. Such applications usually involve the placement of large numbers of bars with close spacing. This steel runs vertically and should lap the same size reinforcing steel out of the footing. square poured concrete beams and columns. 8 ). The Rebar and Concrete in a Slab calculator computes the total length and weight of rebar and the volume of concrete needed for a slab. And a cross-sectional area of 0. long-term deflections of the slabs. E discuss natin dito ang Lapping Zone, Lapping length, Stag. The spacing of such shrinkage-temperature steel cannot exceed 18 in. If you are using high shrinkage concrete, you might want to decrease the cut spacing. 3 Slabs-on-ground with turned-down footings. We had twisted square bars in our 1911 second floor slab. The numbers range from #3 (smallest) to #18 (largest). And the rebar details of (1) is 10mmØ @ 8″ c/c. 5” long, are typically dosed at the rate of 60-68 pounds per cubic yard. Generally, you do not need rebar for a 4-inch slab. My understanding of slabs based on limited experience and a heck of a lot of reading here is:1. Marine Plywood Requirement Area of each marine plywood = 2. Dynamic and/or oscillatory. rt i 2nd layer walij-dwls longit #4@ 12" ole 11'9 "t_ "-1)_-item qty part or no. Steel reinforcement bar size for footing of G+2/ 3rd floor building:- we will assume a structure of G+2 (three storey) residential building, using standard 4″ thick walls, according to general thumb rule, use of mesh bar of 12mm or number 4 (#4) size (diameter) of steel reinforcement as main and distribution bar (T12@6″C/C of Fe500) is most suitable for. I maintain a concrete cover of 40 MM. For general purpose concrete slabs with 2,500 pounds compression strength, like patios, use a 1:2:4 concrete mix ratio. Scanning and Detecting Rebar in Concrete. How far apart must rebars normally be spaced? There should be a clear distance at least equal to the bar diameter between parallel bars but never less than one inch. 2. This design approach is sometimes referred to as continuously reinforced or joint-less slabs and allows numerous, closely spaced (3 to 6 feet), fine cracks to occur throughout the slab. However, for post-tensioned (PT) slabs, this can be mistakenly regarded as difficult, expensive, and. This design is particularly effective for structures with consistent loads. This table is span based since the bottom reinforcement is designed span by span. h. For driveways and patios, #4 (1/2 inch diameter) rebar is a common. Why Does Concrete Require Rebar? Most concrete requires some type of reinforcement. Glass fiber reinforced polymer. Use VERIA's free construction material quantity calculator to aide you in estimating for the materials and labor man-hours of all your construction projects. 5 m) with mini-mum slab thicknesses of 6 to 10 in. Finally, you pour the concrete into the molds. For this case, the lift should not be installed without. #4 rebar is commonly specified to reinforce the thickened edge. 5-TM 5-809-1/AFM 88-3, Chap. Since this is a patio, you could use 6x6 10/10 wire mesh instead of the rebar. Divide your result by the spacing measurement: 180 in / 14 in = 12. The procedure: Lay up the first 4-foot height of wall. Many concrete slabs for homes, driveways, garages, and sidewalks are built according to standard thickness recommendations and do not require a specific. What size rebar do I need for a 6 inch slab? The size of rebar needed for a 6 inch slab would depend on the specific application and requirements. In the Philippines, buildings face various environmental challenges such as strong typhoons, earthquakes, and floods. Concrete slabs: Contractors often use the 1/8 rule for determining the size of steel for a slab. Rebar is typically used to provide additional strength and rigidity to concrete slabs, so if the slab is intended. Grade 40 means that the yield strength is 40,000 psi and the code allowed strength is 20,000 psi. , and unfactored live load = 100 psf. ACI 302. It may be desirable to tie and reinforce the new slab to the pre‐existing surrounding floor. There are two types of Grade slabs: Usually after casting Plinth beams. If consolidation of plastic soils is determined to be a potential problem a suspended slab may be the only effective solution, in which. Types of Slab Construction ACI 360. This is essential to know how much Rebar for the concrete slab is required. 2 cm) from the bottom of the concrete, and side clearances range from 2 to 4. Crack Control – when crack widths are not checked by calculations No Further Checked Required. ASCE, SECB COURSE CONTENT Slab on Grades Construction: Introduction Concrete slabs on grade are a very common type of concrete construction. 60 per square foot. For multi sided slab, first draw the shape: 1: Hit Clear + Start and enter Side Length of first side to draw, then hit appropriate direction (Arrow) button to draw. 4. Two-story buildings require a minimum of 15-inch wide footings for 1,500 LBV soil. Modeling floor diaphragms. For beams, these distances are 300 mm, 180 mm and 150 mm for grades of main reinforcement of Fe 250, Fe 415 and Fe 500, respectively. The minimum Sub-Base thickness shall be as shown in the table. Q. In a typical reinforced concrete building, reinforcement bars arranged as mats are incorporated into a concrete plate of minimum thickness 125 mm to form a reinforced concrete solid slab. Rebar is typically made of different types of steel. c. This calculator uses 35% of balanced rebar area as the steel area for design of slab. (i) The maximum spacing between two parallel main reinforcing bars shall be 3dor 300mm or whichever is less, and. a car weight. That is, there are breaks in the rebar along the runs. We can also pinpoint the depth of every object we locate in concrete with an accuracy of +/- 10-15%. girder sides & slab on grade - 1 reinforced concrete beams 6 mm for every 4. You’ll also need vertical rebar hooks protruding at least 6” into the footing and out at least. less than around 0. Its primary purpose is to increase the tensile strength of the concrete, helping it resist cracking and breaking. Retaining Walls: The most commonly used rebars in retaining walls are #3, #4 and #5. I am confused about the grid. The spacing of the main steel in a slab should not exceed the following:First, the American Concrete Institute (ACI) Residential Code Requirements for Structural Concrete (ACI 332-14) requires contraction joints and provides a table to determine joint spacing for plain and reinforced concrete containing up to 0. If 1 span is 8,000mm, 4,000mm will be center part and add 40times (40d) + rebar thickness is the length of top rebar in center part & end. f. Total Weight of rebar in pounds. A typical installation uses 6-inch by 6-inch woven wire mesh, which is supported on rebar chairs so it is positioned near the center of the finished slab. In order to calculate this, you need to input the length and width of your slab. This type of slab is used on the Basement floor. Fo r decades ACI 318 has re q u i r ed high-Concrete slab-on-ground floors shall be designed and constructed in accordance with the provisions of ACI 332 and this section. Our engineers wanted to make sure that big yellow boots fit between the rods so the workers did not stand on the rod and bend or. 15% of the slab’s cross-sectional area), the spacing of tendons in at least one direction shall not exceed the smaller of eight times the slab thickness and 1. Minimum tensile strength of concrete: 4,000 PSI. We recommended to use 5″ rcc roof slab thickness 1, 2 and 3 storey building. 5% reinforcement (reproduced here as Table 1). The Building Structural Standard defines a two-way slab system as a concrete slab system in which two rebars are arranged in two directions regardless of the presence or absence of a beam that transmits a load to. -Multishearing. x 20 in. For foundations that are taller than 8 feet and slabs thicker than 8 inches, the minimum spacing should range from 7. Minimum reinforcement is 0. Make sure it is in the very center of the slab as if it is too close to the top or bottom it is also useless. Fa b r ic may also be supported at the center of the slab, or it may be installed in two flat layers with the top layer (nega-t i v e steel) extending on either side of the support for one-quarter of the span (See Fi g u r e 1). 2R for suspended floors. Vertical rebar every 16 inches. 5. Minimum spacing between reinforcement bars in foundation tie-beams Concrete casting in foundation tie-beams is not an easy procedure. For example, one-way slab thickness. In either case, blocks should be used under the reinforcement to keep centered. And rebar is sized by eights of an inch. The openings are square in shape and range in size from 2 ft to 5 ft. ”In particular, for slabs containing less than minimum quantities of conventional tensile reinforcement (i. If the slab is more than 24 inches thick, #5 (#5/8 inch diameter) rebar may be required. The following guidelines given below according to BS 7973-2:2001. For example, if a 6-inch-thick slab is used with #3 rebar at 18 inches on center, the percentage of steel for a 12-inch width would be: (0. The main reinforcement of the slab panel “A” is marked as (1). : Regarding reinforcement in slabs, please clarify whether you find a rebar spacing of 16 inches as good in reducing crack widths as a spacing of 6 or 8 inches, assuming there is the same total area of reinforcement in any case. 04% to 0. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. 8 mm) when subjected to 50 pounds (23 kg) applied over 1 inch square (645 mm) of material and are greater than 1/ 8 inch (3 mm) in thickness in the uncompressed state shall not extend beneath walls, partitions or columns, which are fastened to the floor. Shrinkage cracks are probably the most common type of cracks in concrete. Overlap joints by a minimum of 12” for #3 and 15” for #4, bind with wire ties, and keep the steel 3” back from the. x 18 in. ACPA Guide Specification | Dowel Bars for Concrete Street and Highway Pavement | ACPA M254-21 April 8, 2021 | Page 4 of 11 CSA-Z245. 7736 m 2. Consider. Floor slab of bottom-most SS or NS and floor slab of NS located above an SS: (i) Slab reinforcements at both external face and internal face shall be H13-. cedures used to design and construct slab-on-grade such as streets, highways, and floors. Rebar Development Length Calculator is a web application that supports the design of post-installed rebar in concrete applications by calculating the necessary tension and compression development lengths required in accordance with ACI 318-19 / ACI 318-14. Part 3. 9 Factored loads Factored dead load = 3. Standard concrete floor slab thickness in residential construction is 4 inches. The structural design of the concrete floor slab on-ground is dominated by the sub-grade conditions and the floor loadings. 2: Repeat and continue to draw complete (closed) shape. For example, if the first slab is at 12 inches and the second is spaced at 18 inches then measure and place your first mark at 9 inches and then continue spacing the marks at. 4. The slab will be 3" thick with 2. extension of existing reinforced concrete (R/C) structural elements such as slabs, walls, and columns (Figure 3), either to facilitate expansion of floor space or to address other functional changes in the use of the structure. Then use USDA NRCS. Next, you put steel rebar every 2 feet to strengthen the bond between the foundation and the footings. Concrete volume calculator plan view diagram. 6 inches. 34 inch (8. To define design strip rules, click the Slab Design Rules button on the Data Entry toolbar. The main bars are usually positioned in the slab’s bottom layer, with a minimum cover distance of 20mm from the slab’s bottom. 2)(12 in. Tie pieces together with rebar ties. ACI 318-14. Inclined length = 0. 3) Shrinkage cracks: As the concrete slab dries after placement, it shrinks. First, enter the concrete slab sizes: length = 6 m, width = 4 m. The second marker expresses the bar size and is demonstrated by a number. of main bars – One = [Lx ÷ bar. Grads Slab/ Slab on grade: The slab which is cast on the surface of the earth is called a Ground slab. 00 m 7 cantilever reinforced concrete beams 18 mm for every 3. By: Olin Wade (Remodel or Move Stuff) The spacing of rebar in a slab depends on the purpose and size of the slab, as well as the climate in which it is being built. . 5 bars; There shall be a minimum clearance between parallel reinforcement bars of 2 1/2 inches;. Fo r decades ACI 318 has re q u i r ed high- Concrete slab-on-ground floors shall be designed and constructed in accordance with the provisions of ACI 332 and this section. Subject: Re: Rebar in shop floor? Kingston,Mi. 30% carbon cont ent and only. In this video i will show you about 2nd Floor Slab Rebar. the slab joint spacing should be the same as for an un-reinforced slab. Wet your concrete after the pour. This how-to guide will show you how a. the calculator will give you the default spacing values (for rebar – rebar it’s 40cm, and for edge – grid it’s 8cm). The minimum size and grade of rebar for slabs depends on a variety of factors, such as the thickness of the slab, the loads it supports, seismic requirements and other factors. There should be a minimum of 3 inches of clear cover from the fi nished surface of the slab. Figure 5. Cutting that rebar ain’t going to do shit, despite all the “engineers” comments to the contrary. 34 and $7. 1. If your two slabs have different spacing for their rebar mats, measure and mark so your dowels fall in the middle of the spacing of the second slab. * BEAMS SHEAR CONNECTORS (IF PRESENT) For M15 concrete, lever arm = 0. Minimum clear cover to reinforcements in slab depends on the. STRENGTH REINFORCEMENT REBAR SPACING GP‐7 SERIES MODELS 4‐1/4” 3000 PSI / 28 Day Aging #6 Rebar 12 In. 0 pounds per cubic yard (0. So, if we have used 12mm dia rebar in column maximum permissible spacing is 72mm and for 16mm dia longitudinal rebar the spacing is 96mm and so on. For residential buildings, a live load of 2000 to 3000 N/m 2 is used as per Indian standards. MINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES) b, c: Soil classes and later soil load d (psf per foot below grade) GW, GP, SW and SP soils 30: GM, GC, SM, SM-SC and ML soils 45:Concrete Floor Slabs On Grade Course# ST-702 EZ-pdh. I was thinking of the following: basement wall 8 inches thick 10 feet high backfilled up to 7 to 8 feet. The pri m a r y differe n c e s b e t w een each type are re i n f o rc e m e n t details and joint spacing. If you are trying to put a new concrete slab on your small-scale domestic project; 6mm (#19), 8mm (#25), and 10mm (#32) rebars will do the job nicely. We would like to show you a description here but the site won’t allow us. diameter) for a house construction are not that many. 15 mm) polyethylene vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the base course or subgrade and the concrete floor slab, or other approved equivalent methods or materials shall be used to retard vapor transmission through the floor slab. For slabs. If the owner can live with cracks over the beams, there is no need to provide negative slab reinforcement. Advertise Here. Sudip Shrestha. 40ft x 15ft dumpster pad, 8" thick with double mat of #4 rebar 16" OC Each way. Next fill the cores with grout and repeat the process--lay another 4-foot. 42d. Clear span of the two way slab = 5000 mm. #5 bars are 5/8”. Build the wall full height, place concrete continuously in 4-foot lifts, and consolidate each lift. The article elaborates the elastic and inelastic methods for design of. Rebar in a concrete slab reinforces it against weather and other external loads. x 20 in. If the slab in question is just for a patio or a similar purpose, #3 rebar with a diameter of 3/8-inch will do just fine. . Figure 1a: Joint Spacing in Meters. 4 rebar in the lower part of the foundation. One reason is simple ease of construction. Rebar being #4 grade 60. (b) A flat slab which is the same as a flat plate except the areas around the columns have. The design of slabs for imposed loads and live loads is based on the type of the building. E. 1 of the 2021 International Building Code (IBC) specifies that the thickness of concrete floor slabs supported directly on the ground shall not be less than 3 1/2″. The thickness of concrete floor slabs supported directly on the ground shall not be less than 3 1 / 2 inches (89 mm). 3: Two-way slabs supported on four sides; Clause 6. spacing requirements and to repeat bar size and spacing as often as possible. Often, concrete contractors don’t have solid runs of rebar anyway. The footings included in this Part reflect the requirements of AS 2870 and apply to the most common types of soil conditions. Wire mesh is better then rebar, if it can be kept up off the bottom of the slab. . ( D) Depth of slab. 1 Flexural Cracking in Reinforced-Concrete SlabsFor mid-depth rebar, the program will use the bottom bar size and spacing options. Rebar. 3. The size of the columns depends on the total load on the columns. Crazing is a result of poor surface curing and only visible in hard troweled slabs. 00 m to 6. Methods used for finding slab thickness varies for different types of slabs. get your rebar grid down, i would use 1/2" on 12" center. Smaller projects like this usually have to sustain minimal loads and a lower tensile strength is more than enough. The size of the rebar depends on the specific application, but typically #4, #5, #6, and #8 rebar are used. 60 per square foot for materials and labor. MotorCity (Structural) 22 May 17 13:44. 87 d Spacing of bar = Design of Continuous Slab Suppose a slab is supported at the ends and also at intermediate points on beams, the maximum sagging and hogging moments to which the slab is subjected to due to uniformly distributed load, can be computed as follows: Let = intensity of dead load per square metre. ) slabs are plate elements used to form the floors of buildings. However, we want to use slabs for the floor elements in this model. Compression is a force that squeezes or crushes, and tension is a force that pulls something apart. To assign a Slab element to the floor, go to Assign>Wall/Slab/Deck sections. DETAILING OF SLABS (For class held on 6th March 07) By Dr. 2 consists of a 3-inch-thick reinforced concrete slab supported by steel beams. #IScodes #Concrete #Concretetechnology Recent & Related Videos Concrete. ) is going to be 5'-6' for 4 ksi concrete anyways. If your two slabs have different spacing for their rebar mats, measure and mark so your dowels fall in the middle of the spacing of the second slab. 1 in2. For example, a slab that is 6 inches thick might have rebar marked as size 6 or 3/4-inch. If you are in a climate subjecting the floor to freezing, get air added to the concrete. 00 m 14 over 6. These slabs are supported directly by the columns and have a completely flat soffit. Avoid using air contents over 3% for interior slabs. I was thinking of going with the same spacing. A flat plate floor with a live load of 100 psf is only about 8% more expensive than one with a live load of 50 psf, primarily due to the minimum thick-ness requirements for. . Reinforced concrete (R. 3. com Ezekiel Enterprises, LLC 301 Mission Dr. The floor has been designed with two mats of steel, 7 1/2" total concrete thickness and 50 ksi steel beams with a single row of shear studs on the beams. spacing, and other details. I'd use: 8" thick concrete wall with #6 rebar at 12" oc EACH WAY with the VERTICAL rebar placed 3/4" clear from the face of the INTERIOR BASEMENT ROOM. To use our rebar calculator, simply input the dimensions and specifications of your project. 5 round bars, respectively, while. The type of rebar used in the construction of a given section of concrete will depend on several. The formula is, Number of bars = (length ÷ spacing) + 1. The minimum spacing between two reinforcement bars should be at least equal to the maximum coarse aggregate dimension plus a margin of 5 mm. 46 and $1. 9 cm)-round bar 05 = part of second floor plan designated by the number 5. 15. ) slabs are plate elements used to form the floors of buildings. (5) Concrete foundation stem walls that are formed by a thickened concrete slab edge as part of a slab on grade floor must be reinforced with one piece of No. FIrst, find number of rods required for main reinforcement and distribution. Generally, a 4-inch slab will not need a rebar if the slab is used for a normal purpose. 1: Calculate The Main bars. This wood sheeting, which should also be stronger than average, will act as a subfloor. 1 Required design elements—Following are the minimum items that should be addressed in the construction Rebar Spacing Basics. It’s not necessarily the placement of the rebar in the slab but the amount of rebar/rebar spacing and the depth of the slab. Corner cracking and joint faulting are reduced by using these bars. 7Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1805. There are four types of two-way slabs. 00 m 4 3. 120 m Length of shorter side of building = 12. I’m on the second floor and the floor is 6 inch concrete slab with I think at least 1 inch steel rebar as reinforcement. A 6-mil (0. Watch on. One-Way Joist Slab Concrete Floors are constructed in a range of sizes with conventional spans. As per the present market rates, the average cost of concrete for a 400-square foot slab, the typical size for a two-car garage, ranges between $583 and $637 or between $1. Basement slabs and interior slabs on grade, except garage floor slabs: 2,500: 2,500: 2,500 c: Basement walls, foundation walls, exterior walls and other vertical concrete work exposed to the weather: 2,500: 3,000 d:. The term "composite steel deck floor slab" is applied to systems in which the steel deck has some mechanical means of providing positive interlocking between the deck and the concrete. Rebar is tied together, using wire, to hold it in place. The splices should have at least 2 ft overlap into the new pour. T F 8. or slab change soffit typical detail for beam 400 dowel 250 300 (typ. Tying the rebar is crucial to ensuring the rebar stays in place and functions as it should. For the footing, it usually comes between 16mm to 25mm dia depending upon the size of the footing and the reinforcement bar used in compression mesh. Reinforcing steel should be properly tied with wire to rigidly support it in its proper. Report Application Issues or. normal rebar sizes (e. The specified compressive strength of concrete shall be as set forth in Section R402. 3. C. Design drawings are used as a base for computing rebar quantity in different structural elements. 8 ). Commonly called “rebar,” these 1/2-inch-diameter steel rods are embedded in the center of the slab to create a grid that extends lengthwise and crosswise to help the concrete better resist pulling and bending forces. In two-way construction, According to Clauses 8. Minimum thickness of concrete slab, beam, column, foundation and other structural members is selected to meet the design requirements as per standard codes. Elevated Slabs - Design. Number of Required Bars Formula = (Length of slab / spacing) + 1. The typical depth for rebar placement for slabs is 2-4 inches. Carbon steel. Y. After pouring concrete walls, they are anywhere from 8 to 10 inches thick. extension of existing reinforced concrete (R/C) structural elements such as slabs, walls, and columns (Figure 3), either to facilitate expansion of floor space or to address other functional changes in the use of the structure. 00 m 7. I have some question regarding the placement of the expansion joints. It create a bending of the slab. By Theodore Neff. Two layers of steel bar reinforcement are needed for secondary containment floors because tank loads induce both positive and negative bending moments in the floor. Dowel bars transmit the weight from one slab to its neighboring slab. Slab depths are typically between 4”-10” (10. Two layers of steel bar reinforcement are needed for secondary containment floors because tank loads induce both positive and negative bending moments in the floor. 12mm. Sand is filled at a height of 0. #3 is most commonly used for patios and driveways, #4 for columns and walls, and #5 for foundations and footers. Tendons today are seven high-strength steel wires wound together and placed inside a plastic duct. If the maximum diameter for slab thickness is 75 mm, so the diameter of reinforcing bars should be 8 mm. Rebar Spacing; D2-8F: 4. First, Get The Number Of Required Bars. The Rebar Calculator contains equations and data used in working with reinforcement bars (rebar) in concrete slabs. First year, cracked! The slab out the back door is 16 X 30, 4". shear stresses at the columns and bending moments in the slab con-3 trol the design. Clear cover of the slab = 25-mm. For M15 concrete, lever arm = 0. Cracking Unexpected cracking of concrete is a frequent cause of com-plaints. Secondly, the type and diameter of steel bar used for a concrete slab’s rebar depends on the design specifications’ load-bearing capacity. Whether the frame is precast, cast-in-place, masonry, or structural steel it can be accompanied by a HollowCore floor slab system. 11. 5 try 100 mm Dead load Slab weight = 2. If the slab is poured against an existing foundation wall or another slab, you would use the #4 or #5 rebar to dowel it to the which ever you are butting too. )(100)/(6 in. 5 m. 10%.